"It will be the perfect technology to allow for the rapid expansion of electric vehicles," Poizner said during a panel discussion focused on housing, transportation and infrastructure.
Another GOP candidate, former Congressman Tom Campbell, later said he also supports nuclear power.
"I think it's part of the mix and we should've been developing it a long time ago," he said.
Republican hopeful Meg Whitman did not attend the conference because she was in San Diego addressing a Fortune magazine event on women's leadership. In a statement, her campaign spokeswoman said the former eBay chief executive also supports bringing more sources of energy online, including expansion of nuclear power.
First, Whitman would favor a discussion "about the technology necessary to make that possible," spokeswoman Sarah Pompei said.
One of the potential Democratic contenders, Attorney General Jerry Brown, said he does not oppose nuclear technology, adding that California should consider all options to reduce its greenhouse gas emissions. Brown, who served as governor from 1975 to 1983, has not announced his candidacy for another term as governor but is contemplating a run.
"I'm not opposed to anything that is going to deal with climate change in a responsible way," he told reporters outside the forum.
Brown said lawmakers "came very close to an acceptable compromise" with recent legislation that would have required California's utilities to get a third of their power from renewable sources but limited the amount they could import from out of state.
Gov. Arnold Schwarzenegger has said he will veto the bills in part because of that restriction.
He signed an executive order establishing the 33 percent mandate with fewer restrictions than were included in the bills, which were pushed by majority Democrats. Utilities will have to meet the goal by 2020.
Brown declined to say whether he favored the legislation because he hadn't read the entire bill but said he supports getting renewable energy from California and from wind, solar and geothermal producers in other states.
Campbell, a former Schwarzenegger finance director, said he also agreed with the governor's decision to veto the renewable energy bills. He said Schwarzenegger's action will achieve the same goal without limiting the power sources available to utilities.
"I thought that was smart, because first of all we may not have all the capacity in California, and secondly you have to balance two things — fairness to the ratepayers who have to pay for this and the desire to support industry in California," Campbell said.
Four of the five leading candidates for governor were attending a forum on such issues as energy, education, transportation, taxes and infrastructure sponsored by the Silicon Valley Leadership Group. The group said its goal was to bring together business, nonprofit and civic leaders to discuss how to make California more competitive.
San Francisco Mayor Gavin Newsom, who is seeking the Democratic nomination, appeared on a panel discussing education. He said investing more money in schools and making sure they operate efficiently should be a top priority for the next governor because California will not be competitive without a skilled work force.
He did not address reporters following his appearance and did not discuss his views about nuclear power.